A250
AZATHIOPRINE COMPLIANCE AND ADVERSE EVENTS IN A COHORT OF PATIENTS WITH INFLAMMATORY BOWEL DISEASE
I Soo, S Randhawa, R Fedorak
University of Alberta, Edmonton, AB
Aims: Leukopenia and hepatoxicity are recognized adverse effects of therapy with azathioprine occuring in approximately 5% of patients with inflammatory bowel disease (IBD). Conventional clinical wisdom dictates serial monitoring of white blood cell count (WBC) and abnormal LFTs as a means of identifying patients at risk of these complications. Nevertheless, evidence to support serial monitoring is lacking and the adherence rate of patients relative to the venipuncture needed to acquire this testing remains unknown. The objective of this study is, in patients with IBD treated with azationprine: (1) to characterize patient compliance with serial venipuncture for monitoring azathioprine-associated adverse events and to (2) determine the incidence of leucopenia and abnormal LFTs.
Methods: A retrospective chart review of patients with IBD initiated on azathioprine between 2007 to 2011 was conducted. All patients on azathioprine were supplied with written and verbal instructions to obtain venipuncture for serial monitoring of azathioprine-associated adverse events.
Results: One hundred five patients (65 Crohn's, 38 ulcerative colitis, two indeterminate) were entered into the study. Mean age 36.7±14.2 yr. 57 male; 48 female. Sixty percent (±41.0%) of patients completed the weekly venipuncture requested by the protocol during the first month of azathioprine therapy. After the first month of therapy only 57.5±28.4% of patients were adherent to the monthly venipuncture protocol. There was no significant difference in adherence between patients started on therapy in hospital compared to an outpatient. Ten (9.5%) patients experienced a WBC =<3.0. Six had a singular episode while two had two, one had three and one had four episodes of leucopenia. All patients had the low WBC within one year of either azathioprine initiation or therapeutic modification including two with 5-ASA therapy initiation and one with an escalation of azathioprine dosage. Patients with low WBC did not develop any clinical sequella as a consequence. The weekly (median 100%, IQR 50% to 100%) and monthly compliance (median 88.5%, IQR 56.5% to 100%) rates were excellent in the group of patients found to have low WBC. Six (5.7%) patients experienced abnormal LFTs. All episodes occurred within one year of azathioprine initiation or therapy modification. No significant illness occurred from the abnormal LFTs. Weekly (median 100%, IQR 62.5=100%) and monthly (69.2%, IQR 45.8% to 89.2%) bloodwork compliance was above average compared to the entire IBD cohort.
Conclusions: Compliance with serial venipuncture to monitor leucopenia and abnormal LFTS associated with azathioprine therapy in patients with IBD is generally poor. Leucopenia and/or abnormal LFTs are generally detected within one year of azathioprine therapy being initiated or modified and patients remain clinically well during these events.